Growth and Survival Temperature Range for Microbes

[Ishan Jain]

Hello Guys

 

I just want to know the growth and survival temperature ranges for Thiobacillus ferrooxidans and Leptospirillum ferrooxidans also the effect of temperature on these microbes.

 

Thank you

 

 

 

[StringJunky]

 

Thiobacillus ferrooxidans is a gram negative, obligately autotrophic and aerobic Proteobacteria. These bacteria are motile, and possess polar flagella. T. ferrooxidans is an acidophile, living in environments with an optimal pH range of 1.5 to 2.5. T. ferrooxidans is also thermophilic, preferring temperatures of 45 to 50 degrees Celsius. The high temperature tolerance of the bacteria may be due in part to its high GC content of 55 to 65 mole percent. http://web.mst.edu/~microbio/BIO221_2008/T_ferrooxidans.html

 

 

Effects of temperature and pH

 

The major reason for the dominance of ‘ Leptospirillum ’over T. ferrooxidans in industrial processes is almostcertainly the ferric/ferrous ratio (redox potential). However, there may be other reasons which contribute to the dominance of ‘ Leptospirillum ’. The optimum pH for the growth of T. ferrooxidans is within the range pH 1.8-2-5. In contrast, ‘L. ferrooxidans’ is more acid resistant than T. ferrooxidans and will grow at a pH of 1.2 (Norris, 1983). With regard to temperature, ferrooxidans is considered to be more tolerant of low temperatures and less tolerant of high temperatures than is ' L. ferrooxidans'. Some strains of T. ferrooxidans are able to oxidize pyrite at temperatures as low as 10 "C (Norris, 1990) but 30-35 "C is considered to be optimal. ' Leptospirillum '-like bacteria have been reported to have an upper limit of around 45 "C (Norris et al., 1986) with a lower limit of about 20 "C (Sand et al., 1993). The majority of continuous-flow biooxidation processes which are used to treat gold-bearing arsenopyrite ores or concentrates operate at 40 "C and pH 1.6 (Dew et al 1997). This is a little below the optimum pH range and a little above the optimum temperature range for T. ferrooxidans but well within the optimum range of most ' Leptospirillurn ' isolates. The preference of T. ferrooxidans for growth at higher pH values is probably not the main reason for the dominance of ' Leptospirillum since there is a report of the adaptation of the bacterium to pH 1.5 after selection in continuous culture (Vian etal., 1986).

http://www.microbiologyresearch.org/docserver/fulltext/micro/145/1/mic-145-1-5.pdf?expires=1500729296&id=id&accname=guest&checksum=D30D49FDBE982BE227625CFEDAC393F3

Edited July 22, 2017 by StringJunky